Anti-government protest leader Suthep Thaugsuban said his movement was not giving up its struggle. Photo: AP

The number of full-time protesters occupying four other sites at key intersections of the city has dwindled to about 4,000 in the past few weeks.

At the height of protests more than 100,000 people took to the streets to demand the resignation of prime minister Yingluck Shinawatra, who declared on Friday she was “ready to die” to stand up for Thailand’s democracy.

Riot police stand guard at the National Anti-Corruption Commission office in Nonthaburi province, on the outskirts of Bangkok. Photo: Getty-Images

The occupation of the sites by protesters sleeping in tents has severely disrupted traffic flows and business in the city.

Speaking during a visit to northern Thailand where she has strong support, Ms Yingluck, Thailand’s first woman prime minister, said Mr Suthep must first end the protests before she could begin talks with him.

Mr Suthep has earlier suggested that he and Ms Yingluck hold a televised debate.

“I’m also the defence minister, meaning I’m like a soldier who has to do his duty until the last minute,” the Nation newspaper quoted Ms Yingluck as saying.

“A soldier has to keep the last stronghold and die on the battlefield. I will die in the democratic battlefield,” she said.

Thailand’s military and key Thai leaders have warned the country faces collapse into chaos unless a way is found to reconcile warring groups.

The violence that has left 21 people dead and more than 800 injured in broad terms pits two groups of Thai elite against each other, one led by Ms Yingluck’s elder brother Thaksin Shinawatra who is backed by rural masses and the other led by influential figures in Bangkok who have the support of the city’s middle class and royalists.

Mr Thaksin, a former prime minister ousted in a 2006 coup, lives in exile to avoid a jail sentence for corruption.